1. Technical Field
The present invention relates to a display device capable of detecting an external contiguous object and to an electronic apparatus, and in particular to a display device with a touch detecting function capable of detecting an external contiguous object approaching the device from the outside based on a change in capacitance and to an electronic apparatus.
2. Description of the Related Art
Touch detection devices capable of detecting an external contiguous object, which are what is called touch panels, have been attracting attention in recent years. Touch panels are attached or integrated on display devices, such as liquid-crystal display devices, and are used for display devices with a touch detecting function. Display devices with a touch detecting function cause a display device to display various types of button images and the like. This enables input of information using the touch panel as a substitute for general mechanical buttons. Such display devices with a touch detecting function including a touch panel require no input device, such as a keyboard, a mouse, and a keypad. As a result, display devices with a touch detecting function have been increasingly used for portable information terminals, such as mobile phones, besides for computers.
Some types of technologies for touch detection devices are known, including optical, resistive, and capacitive technologies, for example. By applying a capacitive touch detection device to a portable information terminal, it is possible to provide an apparatus having a relatively simple structure and requiring less power consumption. For example, Japanese Patent Application Laid-open Publication No. 2012-221485 (JP-A-2012-221485) discloses a capacitive touch panel.
In a display device with a touch detecting function, a display function and a touch detecting function are integrated with each other, so that an operation for touch detection may affect a display, for example. In contrast, with the display device with a touch detecting function disclosed in JP-A-2012-221485, influence on the display can be reduced even when a touch is detected. The display device with a touch detecting function disclosed in JP-A-2012-221485 includes a drive unit that selectively applies a direct current (DC) drive voltage VcomDC or an alternative current (AC) drive signal VcomAC to a drive electrode. In the display device with a touch detecting function, a display element is driven for display, a drive signal is applied to the drive electrode, and a signal corresponding to the drive signal is output from a touch detection electrode. Accordingly, two pieces of wiring for supplying the DC drive voltage VcomDC and the AC drive signal VcomAC to the drive electrode need to be routed in a picture frame area.
In the display device with a touch detecting function disclosed in JP-A-2012-221485, a resistance of the wiring that supplies the drive signal may affect a time constant of a waveform of the drive signal, and may affect accuracy in touch detection. Due to this, to reduce a connection resistance, a width of the wiring needs to be increased. However, when the width of the wiring is increased, the picture frame area that does not contribute to a display area may be enlarged.
The present invention is made in view of such a situation, and provides a display device with a touch detecting function and an electronic apparatus that can enhance the accuracy in touch detection or narrow the picture frame area.